Apex domains cannot have CNAME records.
Question and response
Question
dig ns1.beyond.pl. NS
Answer
ns1.beyond.pl. 3 NS ns1.beyond.pl.
ns1.beyond.pl. 3 NS ns2.beyond.pl.
Authority
The response has no authority records.
Additional
ns1.beyond.pl. 3 A 193.187.70.10
ns2.beyond.pl. 3 A 193.187.70.20
ns1.beyond.pl. 3 AAAA 2a02:957:0:0:0:0:0:10
ns2.beyond.pl. 3 AAAA 2a02:957:0:0:0:0:0:20
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0